javac is not working and giving message "javac is not recognized "

javac is not working and giving message "javac is not recognized "

i made a simple java file with extension .java and i have also set javac
path variable C:\Program Files\Java\jdk1.7.0_25\bin but it's not working
and giving message "javac is not recognized as an internal or external
command , operable program or batch file " .